Situated on the slopes of the mountain of the same name, Cetona retains the characteristic structure of mediaeval settlements.
The walls once had three circuits, and today the round Rivellino tower, built in the mid-16th century, is the most important remaining trace of the third circuit. The urban structure bears the mark of the wars in the Middle Ages, when Siena and Orvieto battled each other for control of Cetona.
Toward the middle of the 1500s, the construction of the square today named after Garibaldi as the new access to the medieval village was the realization of a dream. The dreamer and driving force behind the Renaissance renewal of Cetona was Gian Luigi Vitelli, also known as Chiappino. Named marquis by the Medici, he wanted to play the part of the good governor by building this oval-shaped piazza, strangely much too big for such a tiny village.
Surrounding it are buildings from the 1600-1700s, including the old Palazzo Vitelli, unrecognizable from the outside, the former 16th-century church of the Santissima Annunziata (today a municipal exhibition space) and, hidden among the houses in one corner, the Church of San Michele Arcangelo, built in 1155 but renovated in the latter half of the 17th century.
The Collegiate Church of the Santissima Trinità is the prettiest church in the town.
Originally built in the 12th-13th century with a single nave in the Romanesque style, an aisle with a small outside portal was added on the left in 1571. The simple interior has some frescoes from the late 1400s, including an Assumption of the Virgin by the school of Pinturicchio (1454-1513).